Abstract: A method is provided for brazing a metal leadframe clip to an electrical resistance heating tip for an electrical resistance igniter, wherein the electrical resistance heating tip includes silicon carbide. The method includes forming a layer of SiO2/Al2O3 on a surface of the electrical resistance heating tip; applying a braze alloy paste between the layer of SiO2/Al2O3 and the metal leadframe clip; and heating the braze alloy, the metal leadframe clip and the electrical resistance heating tip to fuse the braze alloy.

Abstract: A method is provided for brazing a metal leadframe clip to an electrical resistance heating tip for an electrical resistance igniter, wherein the electrical resistance heating tip includes silicon carbide. The method includes forming a layer of SiO2/Al2O3 on a surface of the electrical resistance heating tip; applying a braze alloy paste between the layer of SiO2/Al2O3 and the metal leadframe clip; and heating the braze alloy, the metal leadframe clip and the electrical resistance heating tip to fuse the braze alloy.

Abstract: An interconnect element for electrically connecting an anode and a cathode in adjacent fuel cells in a fuel cell stack, wherein said interconnect element has at least one featured surface including dimples, bosses, and/or pins arranged in a two-dimensional pattern. Preferably, both surfaces are featured, as by mechanical dimpling, embossing, or chemical etching, so that protrusions of the interconnect surface extend into either or both of the adjacent gas flow spaces to make electrical contact with the surfaces of the anode and cathode. This permits conduction of heat from the anode. The protrusions create turbulence in gas flowing through the flow spaces, which increases hydrogen consumption at the anode and hence electric output of the cell.

Abstract: An igniter for igniting combustible gases in a hot zone, such as in a solid oxide fuel cell, comprising a subassembly including an electrical resistance heating tip comprising SiC, metal leadframe clips formed of a nickel-based superalloy and attached to the heating tip, wire leads formed of a nickel-chromium alloy and connected to the leadframe clips for supplying electric current to the heating tip, and a nickel-based braze alloy comprising palladium and cobalt for connecting the leadframe clips to the heating tip and to the wire leads; an alumina ceramic body for receiving the brazed subassembly; and a potting compound comprising zirconia for potting the subassembly into the alumina ceramic body.

Abstract: An improved multiple-tube catalytic reformer comprising a tubular body containing a radiator core having a plurality of longitudinal cells for low-pressure flow-through of combustion gases, the core being formed preferably either by winding of corrugated metal or as an extruded metal monolith. A plurality of reformer tubes, preferably non-cylindrical, containing hydrocarbon catalyst are arrayed in longitudinal openings within the radiator core and preferably are brazed thereto to maximize heat transfer from the radiator core to the reformer tubes. During manufacture, the metal radiator core is economically bored by laser cutting to form the openings to admit the reformer tubes for brazing. Preferably, the reformer tubes are numbered, sized, shaped, and arrayed to minimize the longest conduction path in the radiator core to the center of any reformer tube.

Abstract: A system comprising a cylindrical housing containing a sorbent cartridge selective of one or more gases in a gaseous mixture. End caps on opposite ends of the housing seal to the ends of the cartridge and direct the flow of gas mixture through a portion of the cartridge. The first end cap has entrance and exit ports for the gas mixture and for a purging gas for cartridge regeneration. The second end cap includes a compartment to receive and return the gas mixture to the first cap exit port. The purging gas follows a similar pathway via the remaining portion of the cartridge. The cartridge is rotatable within the housing; thus, the exhausted portion of the medium may be rotated into position for regeneration while a regenerated portion of the medium is rotated into position for re-use, thus providing continuous adsorption from the gas mixture.

Abstract: An electrical interconnect for a solid-oxide fuel cell stack assembly, including a novel sintering paste and an improved manufacturing process for an anode and cathode electrical contacts is disclosed. On the anode side, the paste contains a metallic oxide such as NiO, and an amount of sacrificial pore-forming particles, such as carbon particles or polymer spheres, which are vaporized during sintering of the paste, resulting in a very porous connection having good electrical conductivity and good adhesion. A preferred level of pore-former in the paste is about 40 volume percent. On the cathode side, the paste contains a noble metal such as for example, gold, platinum, palladium or rhodium, and an amount of the sacrificial pore-forming particles. The paste may be applied to the surfaces in a grid pattern or, because the resulting contact is porous after sintering, it may be applied as a continuous layer.

Abstract: An improved multiple-tube catalytic reformer comprising a tubular body containing a radiator core having a plurality of longitudinal cells for low-pressure flow-through of combustion gases, the core being formed preferably either by winding of corrugated metal or as an extruded metal monolith. A plurality of reformer tubes, preferably non-cylindrical, containing hydrocarbon catalyst are arrayed in longitudinal openings within the radiator core and preferably are brazed thereto to maximize heat transfer from the radiator core to the reformer tubes. During manufacture, the metal radiator core is economically bored by laser cutting to form the openings to admit the reformer tubes for brazing. Preferably, the reformer tubes are numbered, sized, shaped, and arrayed to minimize the longest conduction path in the radiator core to the center of any reformer tube.

Abstract: An igniter for igniting combustible gases in a hot zone, such as in a solid oxide fuel cell, comprising a subassembly including an electrical resistance heating tip comprising SiC, metal leadframe clips formed of a nickel-based superalloy and attached to the heating tip, wire leads formed of a nickel-chromium alloy and connected to the leadframe clips for supplying electric current to the heating tip, and a nickel-based braze alloy comprising palladium and cobalt for connecting the leadframe clips to the heating tip and to the wire leads; an alumina ceramic body for receiving the brazed subassembly; and a potting compound comprising zirconia for potting the subassembly into the alumina ceramic body.

Abstract: An electrical interconnect for a fuel cell assembly comprising a peripheral frame formed of one or more materials having a coefficient of thermal expansion similar to that of adjacent elements to which the interconnect must be bonded and a central portion formed of a corrosion-resistant material for conducting electric current between adjacent fuel cells. Preferably, the central portion is attached to the peripheral frame via a brazed corrugated lap joint for relieving thermal expansion differences between the frame and the central portion. Preferably, the joint includes an interlayer of a ductile material, for example, a nickel, copper, silver or gold layer, which helps to relieve thermal stress between the frame and the central portion.

Abstract: In a solid-oxide fuel cell system, a fuel/air manifold conveys air and tail gas fuel from the anodes in a fuel cell stack assembly to a tail gas combustor, producing a heated combustor exhaust having the highest mass flow in the system. The exhaust is passed through a heat exchanger to warm incoming cathode reaction air, and the exhaust is partially cooled by the exchange. From the heat exchanger, the exhaust gas is passed through a tempering jacket space surrounding the fuel cells in the stack. During start-up of the system, the exhaust gas is hotter than the stack and so the warm-up period is shortened. During normal operation of the system, the exhaust gas is cooler than the operating temperature and therefore cooling of the stack is assisted by contact with the exhaust gas.

Abstract: A catalytic reformer assembly including a reactor comprising a plurality of parallel tubes arranged within a tubular housing. A metal substrate, formed preferably as a metal foam lattice, is brazed to the tubes on both their inside and outside surfaces. A catalytic washcoat is applied to the metal substrate within the tubes, defining thereby the tubes as individual catalytic reforming reactors. Endothermic reforming reactions within the tubes are supported by heat from hot combustor exhaust flowing around the tubes in contact with the augmenting heat transfer metal substrates outside the tubes. Radial temperature gradients are small because of excellent heat transfer across the tube walls, resulting in excellent mechanical stability of the washcoat on the metal substrate. Preferably, the tubes are formed of Inconel 625 and the metal substrate is formed of Fecralloy®, a high temperature alloy having excellent thermal conductivity and oxidation resistance.

Abstract: A system comprising a cylindrical housing containing a sorbent cartridge selective of one or more gases in a gaseous mixture. End caps on opposite ends of the housing seal to the ends of the cartridge and direct the flow of gas mixture through a portion of the cartridge. The first end cap has entrance and exit ports for the gas mixture and for a purging gas for cartridge regeneration. The second end cap includes a compartment to receive and return the gas mixture to the first cap exit port. The purging gas follows a similar pathway via the remaining portion of the cartridge. The cartridge is rotatable within the housing; thus, the exhausted portion of the medium may be rotated into position for regeneration while a regenerated portion of the medium is rotated into position for re-use, thus providing continuous adsorption from the gas mixture.

Abstract: In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, oxygen getter devices containing oxygen-gettering material such as metallic nickel are provided in the fuel passageways leading to and from the anodes. Oxidation of the oxygen-gettering material is readily reversed through reduction by fuel when the assembly is restarted.

Abstract: A fuel cell assembly comprising a plurality of individual fuel cells, especially a solid-oxide fuel cell assembly. The cells are organized into a plurality of stacks, preferably two stacks, disposed side-by-side rather than end-to-end as in a prior art monolithic single stack. This arrangement makes the assembly compact physically, which can be highly desirable in some fuel cell applications. The stacks are connected conventionally in series electrically but are supplied with air and fuel in parallel to shorten the distribution manifolds and improve uniformity of distribution and exhaust among all the cells.

Abstract: A solid-oxide fuel cell system comprising a plurality of components having mating ports therebetween, the port interfaces being sealed by gaskets that include fluorophlogopite mica (F-mica).

Abstract: A fuel cell having a non-uniform electrical resistivity over the flow area of the cell. Resistance is higher in areas of the cell having locally low levels of hydrogen than in areas having locally high levels of hydrogen. Excess oxygen ion migration and buildup is suppressed in regions having low hydrogen concentration and is correspondingly increased in regions having a surfeit of hydrogen. Destructive oxidation of the anode is suppressed and a greater percentage of the hydrogen passed into the cell is consumed, thereby increasing electric output.

Abstract: Interconnects and perimeter spacers for a fuel cell stack are provided as flexible elements which can conform to non-planarities in a stack's electrolyte elements and thereby avoid inducing torsional stresses in the electrolyte elements. The interconnects are foil elements about 0.005 inches thick, formed of a superalloy such as Hastelloy, Haynes 230, or a stainless steel. The perimeter spacers comprise a plurality of laminate thin spacer elements, each thin spacer element being a laminate of superalloy and a “soft” material such as copper, nickel, or mica. The spacer elements can slide past one another; thus the perimeter spacers can be physically thick, to form the gas flow spaces within the stack, while also being torsionally flexible.

Abstract: A solid-oxide fuel cell system comprising a plurality of components having mating ports therebetween, the port interfaces being sealed by gaskets that include fluorophlogopite mica (F-mica).

Abstract: In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, check valves and oxygen getter devices containing oxygen-scavenging material such as metallic nickel are provided in the reformate passageways leading to and from the anodes. The check valves preferably are closed by gravity. Oxidation of the oxygen-gettering material is readily reversed through reduction by reformate when the assembly is restarted.